Telephone system



1,637,403 H. H. ABBOTT TELEPHONE SYSTEM Filed March 9,- 1,926'

Patented Aug. 2, 1927.r

UNITED )STATES PATENT oFFIcn HENRY n.y ABBOTT, or NEWYORK, N. Y., AssieNoe To AMERICAN TELniHoNn AND yTELnefiiAiH COMPANY, A ooiiPoiiATieN on `NEW YORK.

TELEPHQNE sYsTiiM.

Application ledrMarch 9, 1926. Sc1ia1'Ne.'93,507.

y This invention relates to telephone. systems, and more particularly to imj'irovcments in trunks i for service ybetweenl ditl'erent switchboards in the telephone exchange.

In present practiceitis customary to eniploy socalled interposition trunks for handling night traHic or traliic duringslack periods. These trunks usimlly` terminate at one end in jacksat so-called patrol opera tors positions located at convenient points on the switchboard at the exchange, easily accessible to the patrol operators. 'Theother rends of thesetrunks terminate in jacks rat stationary operators positions,kthat is, positions regularly 'occupied during' rslack periods.r f

The duties of the patrol operators are, kas the naine implies, to patrol dui-.ingr slackperiods entire Lsections of switchboards or groups oit positions not occupied by the ree ular operators. These patrol oj'icrators, on noting lighted lamps in any ot these switchboards indicatingr calling' subscribers, estab-r lish connect-ions -troni the corresponding subA scribers jacks through interposition trunks terminating in a position or positions where stationary operators are in attendance that thesestationary operators may attendy to the calls. f f

The principal objects oiE this ,inventionk are 'to provide simplified interposition trunks oit this lgeneral type, wherebytheproccsses oi establishing and handling kconnections thoreovcr between a callingv subscriber-s line and ay stationary opera-tors position. are at all times properlyyan expeditiously supervised; whereby the 'freeing oi the calling;` rsubscriber-s line 'from suolir a connection is accomplished without delay, that is, without waiting for the patroling operator to break down the connection and whereby'the subscribers charge on either the .so-called Vflat rate or the so-called message rate basis may i ybe attended to with equal eapedition.`

To attain these and other objects which ywill hereinafter appear, there is provided in accordance with the preferred form ot the invent-ion, in a speciiic aspect, aninterposition'trunk circuit having' supervisory means` whereby, on the connecting or patching of 'the interposition trunk to a calling sub-v scribersj line, this subscribers line lamp is extinguished; 'whereby this subscribeids liuc i busy; whereby signals are.

gi ,In ziele given. atthe position or positions wherethe iree end .of the interposition trunk employed terminates to notify the stationary operators thereat vthat a connection over this particular interposition trunk is desired andwhereby ont-he answering of this call by a stationary` operator by the insertion rof plug into a jacket this interposition trunk, these sig,- nals are extinguished. 'i

Other features, oit' theA invention are -a supervisory kcircuit means, whereby, in yre sponse to the termination ot theconversation between the calling and called sub scribers and the disconnection of the stationtrunk, the calling subscribers lineis freed from the interposition trunk, kthat is, in this sense that the calling subscriberniay again call the patrol operator by lighting hisline lamp before the previous connection between the calling subscriber and the' interposition trunkemployed has been taken down, or that the calling subscriber may himseltl be called under these circumstances; and ymeans whereby in response to the disconnection of the' stationary operators cord vtrom the connection, ya signal is given at the patrol op- :erators position to indicate to her that the' conversation between the subscribers is terminated. f Another feature of the yinvention is the provision.otsupervisory means whereby, it the calling subscriber is to be charged for "the call on the flat rate`basis,vthe signal at the ipatrol roperators position y is steadily lighted on the disconnection of the station# rary operators cord 'from the interposition r"trunk employed and whereby, if the calling subscriber is to be charged'fort-he call on i circuitemployed by her 'torextending the 'connection to a called. subscriber, the signal at the operators position is caused 'to flash.

ornifhasbeen illustrated in theaccoinpanyintdraivmgs, in which FigureV lshGWs an 't the i message igt-gister; a; patching; tiid iter The invention in its ypreferred specific enA `ary operatoscord from ythe interposition sar tors positions D and E.

the use of the patrol operator and an interposition trunk arranged in accordance With this invention for extending a connection to a stationary operators position; While Fig. 2 illustrates ay portion of an ordinary Ystandard cord circuit equipped With a message register circuit.

Referring now to Fig. l, the interposition trunk illustrated may be arrangedV so that jacks l, 2 and 3 and the corresponding lamps 4, 5`ancl 6 are located, respectively, at patrol positions A, Band C. These patrol positions may be arranged at strategic points Ythroughout the exchange in the sect-ions or such yas 22, through jack 23 to jack lof the interposition trunk, Whilethe cord circuit shown in Fig.v 2 may be used either'by a patrol operator W ier..V a call'is to be charged Y on the message rate basis or by a stationary operator for establishing a call over an interposition trunk to a called subscribers line and when a call 1s to be charged on 4either the fiat rate or the message rate basis.

To more clearly set forth the features vof this invention as embodied in the interposi tion trunk circuit shownunder different conditions. descriptions will be made 1n the following text of the specilication, first. of a call extended over this trunlr when the calllng subscriber of line is to be charged on the fiat ratejbasis, followed by a descripL tion of the functions thereof when the call ing subscriber is to be charged on the message rate basis.

Referring now to the establishing'of call to be e2-:tended on the flat rate basis, the subscriber of line 22, ron lifting his receiver from the hook,l causes the lighting of lamp 30 by the operation ofk relay 3l. rlhe patrol operator, on noticing the lighting of this lamp, extends the call to Ya stationary operators position by inserting' plug. of patching cord 2O into jack 23 of line 22 and plug 35 of this patching cord into jack l of theinterposition trunk. This jack vis located at the patrol operators positionV A, it being assumed that this position is located at the shortest distance from the'position Where the line lamp 30is Vlighted and the corresponding jack 23is` located. Y It should be understood that if eitherl position B or C is located nearer than position A to jack 23, the corresponding jacks 2 or 3 Vmay, be employed for extending the connections to a stationary7 operators position. The firstresult of this patchingofv the connection from the subscribers line 22 to the intcrposition trunlr is that line lamp 3() is extinguished by the operation of the cut-olf relay 3G over a circuit as follows: battery, resistance 3T, outer right-handarmature and baclr contact of relay 38, left-hand lonT resistance Winding of relay 35), sleeve terminals of jack l and plug 85, sleeve conductor of the patching cord 20, sleeve terminals of plug 33 and jack 28, winding of cut-olf relay 36 to ground. Relay 39 also operates in this circuit and closes a circuit for the operation of lamps l2 and 1S at the stationary operators positions D and E as follows: battery-lamps l2 and 13 in parallel, leftand armature and bach contact of relay 38, right-hand inner armature and-.back contact of relay Ll0, righthand armature and baclr contact of relay 42, armatureand front Contact of relay 89` to ground. y

rhe lighting of lamps l2 and lindicates to the stationaryoperators of positions l) and E that a connection is desired over this particular interposition trunk. Either one of these operators may now insert a plug, such as s? ofb the cord illustrated in Fig. 2, into jacl; 10er ll of the interposition trunk. lf it is assumed that the stationary operator at position D is the one that attends to the call, a circuit Will now be completed for the operation of relay 420 as follows: battery, supervisoryV lamp Lll-5, sleeve terminals of plug and jack l0, 'Winding of relay all to ground. Relay 40, in operating, lauses lamps 13V and l2 to bc extinguished by the opening' of the circuit for these lamps at the inner armature and back contact of relay Ll0. A. circuit for the operation of relay 38 is also established by the operation of relay 40, as follows: battery, winding of relay 3S, makebefore-break contact of relay 38, righthand inner armature andr front contact of relay Ll0, right-hand armature and back con tact of relay l2, armature and front contact of relay B9 to ground. Relay 3S in operating closes a locl-ring circuit for itself through its inner right-hand armature and front contact to the ground at the armature and front Contact of relay 39. It should be noted that on the insertion of plug into jack l0 and the operation 0of relay LlO, a circuit parallel to the circuit for relay 4l() is established through the left-hand Winding of relay 42 to ground at the outer right-hand armature and front Contact of relay 'lO, but.- as the operating characteristics of relay 42 are marginal, this relay does not operate at this time. lt should be noted that on the operation of relay 3S the circuit from battery through the resistance 3T and the left-hand Winding of relay 3S) to operate relay 36 is broken butthis is of no importance as this 4l() through the left-hand armature and front lill! lll) contact of relay 40, so tliatkno change inthe circuittales place aty this time as far as the operation of the cut-oil relay 36 is concerned.r

. and this operator will nowinquire from the ,calling subscriber as to the desired connec- ,K tio-ii, rand on obtaining this information, this operator ymay complete the connection to the The stationary operator at stationDis now connected directly to the subsciiiljierls line wanted subscriber and conversation between the calling andy called subscribers may take place in the usual manner. f

lVhen the conversation between these ytwo subscribers has terminated, fthe stationary i operator at position D may remove `plug 45 ance than the resistance 37,y relay 436 ivillfre-k lease while relay 39 will remain operated. The relea'segot relay 36 causes the calling subscribers line 22 to be restored to lnormal condition even though the patching cord 20 has not yet been removed from the connec# tion. The rpurpose of restoring the line 22 fto its 'normal position is primarily kto enable thecalling subscriber oit this line tok be called again quickly, that is, before the patrol operator has opened theconnectioii ot' this line 'tot the interposition trunk used in the previous connection. This is of particular iinportance the patrol operator may not be able kto remove the patching cord 20 as quickly as may be desired. f f j y Another effect of the release of relay 40 .is

the` lighting' ot lamps r4, 5 and 6 to indicatey to the patrol operators that conversation between the calling. and called subscriber over this particular interposition trunk has teil'- minated.r The circuit for' these maybe traced as follows: battery, lamps 4, and 6 in parallel,lefthand armature and :trent contact of relay 38, inner riglit-hand armature and back contact of relay 40, right-hand armature and back contact of relay 42, arh mature and `front contact of relay 39 t0 ground. The patrol operator kat kposition A,

on noting the lighting of lamp 4, removes patching cord from jacks 1 and 28.

In case ythe calling subscriber of line 22 desires'a second connection before the patrol operator has removed the patching cord 2O trom jacks 23 and 1, lamp k80 will be lighted and the patrol operatory will then understand that a second connect-ion is desired. She will y then simply` remove plug rtemporarily from jack 1 to ycause the release of relays 39 and 38 and thus restorethe interposition office trunk circuit to normal and then reinsert plug 35 into jack l. a second time. The

ywith its left-hand winding. isfoii such character that sufficient current functioning of' the interpositiontrunk in this [case will be the same as hereinbefore described. n It shouldfbe noted that on establishing a connection tothe interpositiontrunk as outy f lined aboveat the patrol position A, the jacks 2 and 3 at pat-rol 'positions'By and C Twill either test busy in the usual manner due to the battery connection on the sleeve of these jacks, or Lindicate a busy condition due to the lighted corresponding lamp.

It, on the yother hand, the subscriber at 22 is to be charged for the call on'tlie message register basis, the stationary operator at p0- sition D, noticing that the conversation be'- tweenfthe subscribers has terminated, will, before removing plug from jack 10,'operate the message register-key 50and thus establish ay circuit as Jfollows: battery, ,position messageregister 5l., message register key 50, sleeve terminals of plug 45 and jack 10, lett-hand winding of relay 42, outer right-hand armature and front contact ot relay 40-toy ground. In this case relay 42 'will operate in this circuit as the battery ap- Vphe'd through the' position messageregister is ofsucli character as to cause this relay tofunction. Relay 42, inr operating, pro.-

' vides a locking circuit for itself through its righthandy winding, right-hand armature and front contact to ground .t the armature `and frontcontact of'relay This relay r4.2 also connects at its lett-hand armature and front contact a resistance 56 in parallel This resistance will now flow through the position message register 5l. to cause itto operate yand register "the call Vinade by this operator at position D,

from jacklO. On the removal of this plug, relay 40 .isreleased and a circuit is now established for* the flashing ot the signals 4, 5 and 6 over av circuit as follows: battery, lamps 4, 5 rand 6, in parallel, lefthand armature and front Contact of relay 38, righthand inner armature and back contact of relay 40, right-hand make-before-break contact of relay 42,.interrupter 58 to ground. These signals 4, 5 and 6 are therefore now alternately lighted and yextinguished through the operation of the interrupter 58.

This/[lashing ot the lamp 4 Will indicate to the 'patrol operator at position A that the calling subscriber is to be charged on the inessagerate basis, that is, that this patrol operator must actuate the message register `thatthe cally has been recorded on register 5l yand this operator may now remove plug 45 60 associated with line 22. `To do this, the

`patrol opei'atormust first remove patching cord 20 from the jacks 1 and 28` and employ Cil this end she Will'insert plug 45 of Asuch a cord into jack 28 and by operating key 50, she establishes a circuit over the sleeve terminals ot plug i5 and jack 23 Vfrom the battery at the message register 5l through the message register to ground. The character ofthe batterj.T connected Vat inessage register 5l is such as to cause the operation ot the message registerO. The lighting oft 4lamp 5T Will indicate to the patrol operator that message register 60 has operated and she may then remove plug l5 from jack 23. lt should be noted that on the removal'ot the plug 35 of patching cord 2O from jack l, rela;vv 39 Will return to normal yand cause the release or relays 38 and L2 Which Vare held operated from the ground at the armature ot relaiT 39 so that the cir-k `With one end ot said trunk for making .saidV line W bus;T andv tor operating the signal at thefother end of said trunk, and ineans responsive to the disconnection of the link circuit-k from the rtrunk for. actuating the sig'- nal at the -said `onen-end of said trunk and tor resto ing the subscribers line to a nonbusy condition, irrespective of the connection'ot the trunk With the subscribers line.

2. ln a vtele )lione sistem a subscriber-s line, 'a link circuit,r an intcrposition trunk for connecting the subscribers line with the link `circuit, a signal associated with the subscribers line actuated 'in response to the initiation ot a call by its subscriber, al trunk sioinaliassociated With each end of the interposition trunk, means responsive to the connection ot the subscribers line to one end ofthe trunk tor disabling the line signal,

for making the subscribers lineY test busy and for actuating the trunk signal located at the opposite vend ot' the trunk, means re sponsive to the connection ot the link circuit to said trunk vfor disabling' the trunk signal yat rthe end connected to said subscribers line, means responsive to the disconnection ot the link circuit from the trunk tor Vactuating said signal in one'manner, a

source ot current associated With said link circuit, andineans responsive tothe application ot current fromV said source to said trunk followed b v vthe disconnection of the link circuit from said trunk for actuating said signal in a clili'eient manner,

4. In a telephone system, a subscribers line, a link circuit, an interposition trunk for connecting saidy subscribersline with said link circuit, a signal associated With said trunk, a marginal relay in said trunk, a source ot currenty associated with said link circuit, meansrin said truuk responsive to the actuation of said rela;7 on the application ot current from said source for partially preparing a circuit tor the actuation of said signal, and meansA thereafter responsive to the disconnection of the link circuiti'rom the trunk tor completing said circuit for thc actuation ot said signal. 1

ln testimonywhereof, I have signed my name to this specification this 8th day of March, 1926. f

HENRY H. ABBOTT. 

